PHP计算两个日期相差的年月日时分秒

$start_time = '2017-09-06 15:12:20';

$end_time = '2018-09-08 10:20:45';

get_time($start_time,$end_time);

function get_time($start,$end){

    $start = strtotime($start);

    $end = strtotime($end);

    if ($start > $end){

        $diff_time = $start-$end;

    }else{

        $diff_time = $end-$start;

    }

    $year_t = 3600*24*365;

    $day_t = 3600*24;

    $hours_t = 3600;

    $minute_t = 60;

    $year = floor($diff_time/$year_t);

    $days = floor(($diff_time-$year*$year_t)/$day_t);

    $hours = floor(($diff_time-($year*$year_t)-($days*$day_t))/$hours_t);

    $minute = floor(($diff_time-($year*$year_t)-($days*$day_t)-$hours*$hours_t)/$minute_t);

    $seconds = $diff_time - $minute*$minute_t-$hours*$hours_t-$days*$day_t-$year*$year_t;

//    $minute = floor();

    echo $year.'年'.$days.'天'.$hours.'小时'.$minute.'分钟'.$seconds.'秒';

}